Catalytic effect of MWCNTs on the dehydrogenation behavior of LiAlH4

Effects of Ni and Co-decorated MWCNTs addition on the dehydrogenation behavior and stability of LiAlH4

“…The temperature at which the sample had 0.25 wt% weight loss was defined as the onset dehydrogenation temperature. For the as-milled LiAlH 4 , the onset dehydrogenation temperature of LiAlH 4 started at 170 C and the second stage dehydrogenation temperature was found at 200 C. With the addition of 20 wt% MWCNTs, the initial dehydrogenation temperature of LiAlH 4 decreased from 170 C to 140 C and the second stage dehydrogenation temperature remained at about 200 C, which was in agreement with our previous results [27]. The decoration of Ni particles further reinforced its catalytic power of MWCNTs in lowering dehydrogenation temperature of LiAlH 4 .…”

“…Other than transition metal based catalysts, carbon based material such as carbon nanotubes [26,27] and carbon nanofiber [28] also exhibit catalytic effect in adjusting the thermodynamic and kinetic properties of LiAlH 4. The nanoesized scaffolds of carbon materials confined the particle size of hydrides [29] and provided an efficient pathway for hydrogen diffusion [30].…”

Effects of TiCl3-decorated MWCNTs addition on the dehydrogenation behavior and stability of LiAlH4

“…Based on the TGA results, the temperature at which the sample had 0.25 wt% weight loss was determined as the initial dehydrogenation temperature. For the as-milled LiAlH 4 , the initial hydrogen desorption temperature was 170 C, in agreement with that reported in the literature [28]. A second dehydrogenation temperature was observed as the sample was continuously heated to 220 C. The total amount of hydrogen released was as high as 6.5 wt% when the temperature was raised to 260 C, and thereafter remained almost unchanged.…”

“…The presence of the diffraction peaks of Li 3 AlH 6 indicated that TiCl 3 eMWCNTs could strongly catalyze the decomposition of LiAlH 4 , even at room temperature. In our previous investigation, the first stage dehydrogenation temperature of LiAlH 4 could be lowered from 170 C to 140 C with the addition of plain MWCNTs [28]. The in-situ synchrotron Xray diffraction results obtained in this study clearly indicate that the catalyzing power of MWCNTs could be substantially promoted with TiCl 3 decoration.…”

“…In an attempt to explain the physical mechanism by density functional theory calculations, Wohlwend et al [21] indicated that the presence of Ti-containing additives in LiAlH 4 might alter the charge density in the surrounding AlH 4 À tetrahedra, affecting the H binding energy and leading to prompt desorption of H 2 [21]. Besides the Ti based catalysts, nano-sized carbon materials such as carbon nano-fibers (CNFs) [25,26], single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs) [27,28], were also reported to exhibit catalytic effects in modifying and improving the dehydrogenation kinetics of complex metal hydrides [28]. A few studies have attempted to explore the roles of carbon additives in catalyzing the dehydrogenation reactions of various complex metal hydrides.…”